This invention relates to tunable laser sources and more particularly to laser sources comprising optically pumped tunable vertical cavity surface emitting diode lasers and optical fiber amplifiers.
Single mode optical fibers doped with rare-earth elements are well known for their high efficiency. However, lasers made with doped fibers as gain medium bear challenges in cavity stabilization. Usually a sophisticated and complex scheme has to be employed in order to obtain a stable and high quality spectral output. A vertical cavity surface emitting laser (VCSEL) with a movable mirror has the advantage of providing a wide tuning range with high quality spectral output, but the efficiency of the VCSEL tends to be limited due to low gain of the cavity. The maximum possible power from an optically pumped VCSEL is further restricted by the difficulty of dissipating heat, which tends to limit full use of the increasingly high power available from single mode pump diodes.
The primary object of the invention is to provide an efficient, high power and high quality tunable laser source.
A further object is to extend the capabilities of optically pumped tunable vertical cavity surface emitting diode lasers.
Still another object is utilize a doped fiber amplifier to increase the power output of an optically pumped VCSEL.
These and other objects are achieved by providing a laser source that comprises in combination a VSCEL, a doped optical gain fiber, a pump laser, and means coupling said pump laser, said VCSEL and said fiber whereby said VCSEL and said fiber are optically pumped by the output of said pump laser and the output of said vertical cavity surface emitting laser is injected into said fiber and is amplified in said fiber by the output of said pump laser. Other features and advantages of the invention will be made clear by the following detailed description which is to be considered together with the accompanying drawings.